A Novel Family of Np(VI) Oxysalts: Crystal Structures, Calorimetry, Thermal Behavior, and Comparison with U(VI) Compounds

Ilya V. Kornyakov, Vladislav V. Gurzhiy, Jennifer E.S. Szymanowski, Lei Zhang, Samuel N. Perry, Sergey V. Krivovichev, Peter C. Burns

Research output

2 Citations (Scopus)

Abstract

Phase formation in the mixed sulfate-selenate Np(VI)-bearing aqueous system has been investigated. The obtained crystalline compounds, Cs 2 [(NpO 2 ) 2 (TO 4 ) 3 ] (T = S, Se), crystallize in the tetragonal system, space group P4 2 1 m, with a = 9.5737(3)-9.817(3) Å, c = 8.0824(4)-8.111(3) Å, and V = 740.79(6)-781.8(6) Å 3 , and have been chemically characterized. Single-crystal X-ray diffraction experiments at various temperatures were used to define the thermal behavior of the crystal structures relative to the S/Se ratio. The thermal behavior of mixed sulfate-selenate and pure selenate compounds is anisotropic, with the highest thermal expansion in the direction perpendicular to the sheets of Np-bearing polyhedra, while the structure of the pure sulfate compound experiences almost isotropic thermal expansion with slightly higher expansion within the layer, which is explained by the influence of stronger Cs-O bonding. High-temperature drop solution calorimetry was used to derive the enthalpies of formation of the Cs + -bearing neptunyl oxysalts. Within this family of isotypic structures, cesium neptunyl sulfate has a more negative enthalpy of formation in comparison to the selenate compound.

Original languageEnglish
Pages (from-to)2811-2819
Number of pages9
JournalCrystal Growth and Design
Volume19
Issue number5
DOIs
Publication statusPublished - 26 Mar 2019

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Selenic Acid
Bearings (structural)
Calorimetry
sulfates
heat measurement
Crystal structure
Sulfates
crystal structure
Thermal expansion
Enthalpy
thermal expansion
enthalpy
Cesium
polyhedrons
cesium
Single crystals
Crystalline materials
X ray diffraction
Temperature
expansion

Cite this

@article{9ed4bb06465a4426a9eea5663dc86bb0,
title = "A Novel Family of Np(VI) Oxysalts: Crystal Structures, Calorimetry, Thermal Behavior, and Comparison with U(VI) Compounds",
abstract = "Phase formation in the mixed sulfate-selenate Np(VI)-bearing aqueous system has been investigated. The obtained crystalline compounds, Cs 2 [(NpO 2 ) 2 (TO 4 ) 3 ] (T = S, Se), crystallize in the tetragonal system, space group P4 2 1 m, with a = 9.5737(3)-9.817(3) {\AA}, c = 8.0824(4)-8.111(3) {\AA}, and V = 740.79(6)-781.8(6) {\AA} 3 , and have been chemically characterized. Single-crystal X-ray diffraction experiments at various temperatures were used to define the thermal behavior of the crystal structures relative to the S/Se ratio. The thermal behavior of mixed sulfate-selenate and pure selenate compounds is anisotropic, with the highest thermal expansion in the direction perpendicular to the sheets of Np-bearing polyhedra, while the structure of the pure sulfate compound experiences almost isotropic thermal expansion with slightly higher expansion within the layer, which is explained by the influence of stronger Cs-O bonding. High-temperature drop solution calorimetry was used to derive the enthalpies of formation of the Cs + -bearing neptunyl oxysalts. Within this family of isotypic structures, cesium neptunyl sulfate has a more negative enthalpy of formation in comparison to the selenate compound.",
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author = "Kornyakov, {Ilya V.} and Gurzhiy, {Vladislav V.} and Szymanowski, {Jennifer E.S.} and Lei Zhang and Perry, {Samuel N.} and Krivovichev, {Sergey V.} and Burns, {Peter C.}",
year = "2019",
month = "3",
day = "26",
doi = "10.1021/acs.cgd.9b00043",
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TY - JOUR

T1 - A Novel Family of Np(VI) Oxysalts

T2 - Crystal Structures, Calorimetry, Thermal Behavior, and Comparison with U(VI) Compounds

AU - Kornyakov, Ilya V.

AU - Gurzhiy, Vladislav V.

AU - Szymanowski, Jennifer E.S.

AU - Zhang, Lei

AU - Perry, Samuel N.

AU - Krivovichev, Sergey V.

AU - Burns, Peter C.

PY - 2019/3/26

Y1 - 2019/3/26

N2 - Phase formation in the mixed sulfate-selenate Np(VI)-bearing aqueous system has been investigated. The obtained crystalline compounds, Cs 2 [(NpO 2 ) 2 (TO 4 ) 3 ] (T = S, Se), crystallize in the tetragonal system, space group P4 2 1 m, with a = 9.5737(3)-9.817(3) Å, c = 8.0824(4)-8.111(3) Å, and V = 740.79(6)-781.8(6) Å 3 , and have been chemically characterized. Single-crystal X-ray diffraction experiments at various temperatures were used to define the thermal behavior of the crystal structures relative to the S/Se ratio. The thermal behavior of mixed sulfate-selenate and pure selenate compounds is anisotropic, with the highest thermal expansion in the direction perpendicular to the sheets of Np-bearing polyhedra, while the structure of the pure sulfate compound experiences almost isotropic thermal expansion with slightly higher expansion within the layer, which is explained by the influence of stronger Cs-O bonding. High-temperature drop solution calorimetry was used to derive the enthalpies of formation of the Cs + -bearing neptunyl oxysalts. Within this family of isotypic structures, cesium neptunyl sulfate has a more negative enthalpy of formation in comparison to the selenate compound.

AB - Phase formation in the mixed sulfate-selenate Np(VI)-bearing aqueous system has been investigated. The obtained crystalline compounds, Cs 2 [(NpO 2 ) 2 (TO 4 ) 3 ] (T = S, Se), crystallize in the tetragonal system, space group P4 2 1 m, with a = 9.5737(3)-9.817(3) Å, c = 8.0824(4)-8.111(3) Å, and V = 740.79(6)-781.8(6) Å 3 , and have been chemically characterized. Single-crystal X-ray diffraction experiments at various temperatures were used to define the thermal behavior of the crystal structures relative to the S/Se ratio. The thermal behavior of mixed sulfate-selenate and pure selenate compounds is anisotropic, with the highest thermal expansion in the direction perpendicular to the sheets of Np-bearing polyhedra, while the structure of the pure sulfate compound experiences almost isotropic thermal expansion with slightly higher expansion within the layer, which is explained by the influence of stronger Cs-O bonding. High-temperature drop solution calorimetry was used to derive the enthalpies of formation of the Cs + -bearing neptunyl oxysalts. Within this family of isotypic structures, cesium neptunyl sulfate has a more negative enthalpy of formation in comparison to the selenate compound.

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KW - DIRECTIONS

KW - NEPTUNIUM

KW - OXIDES

KW - PROGRESS

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DO - 10.1021/acs.cgd.9b00043

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JO - Crystal Growth and Design

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